Environmental Management Branch
Environmental Management Branch
Lozier T.M.,University of Waterloo |
Macrae M.L.,University of Waterloo |
Brunke R.,Environmental Management Branch |
Van Eerd L.L.,University of Guelph
Agricultural Water Management | Year: 2017
In northern climates, crop residue and cover crops are potential sources of dissolved reactive phosphorus (DRP) to runoff; yet, there are few field studies to quantify this. The objectives of this study were (1) to quantify changes in water extractable phosphorus (WEP) concentrations in the residues of Triticum aestivum L. (winter wheat), Trifolium pretense L. (red clover) and Avena sativa L. (oat) cover crops and surface soil in two agricultural fields (ILD and LON) over the non-growing season (NGS); and (2) to determine if changes in WEP in vegetation residue or soil were reflected in loads of DRP or total P (TP) in surface runoff and/or tile drain effluent. Concentrations of WEP in cover crops were larger than those in wheat residue and soil. Water extractable P concentrations in vegetation increased with plant decomposition and decreased following runoff events indicating that the plant WEP was mobilized in runoff. Differences in WEP concentrations were not observed with topography, with the exception of the period following snowmelt when low-lying areas prone to surface inundation were depleted relative to upland locations. Although WEP appeared to have been mobilized from vegetation and soil pools, loads of DRP (0.165–0.245 kg ha−1) and TP (0.295 kg ha−1–0.360 kg ha−1) leaving the fields were small in comparison to P pools in cover crops (7.70 kg ha−1 oat, 1.70 kg ha−1 red clover), wheat residues (0.03–0.06 kg ha−1) and soils (1.39–5.87 kg ha−1), suggesting that much of the P released from vegetation was retained within the field. This study provides insight into the timing and magnitude of P release from vegetation throughout the non-growing season in regions with cool temperate climates, and provides an improved understanding of the contribution of cover crops to winter P losses. © 2017 Elsevier B.V.
Joosse P.J.,Environmental Management Branch |
Baker D.B.,Heidelberg University
Canadian Journal of Soil Science | Year: 2011
Over the past decade, scientists have been discussing the re-emergence of harmful algal blooms and excessive growth of Cladophora in some areas of the Great Lakes. An observation that has emerged from these discussions is that management of non-point or diffuse sources of phosphorus will be more important in the future in order to address symptoms of eutrophication in the nearshore. This paper provides context for this renewed focus on managing non-point source tributary loads and is based primarily on materials and discussions from the Great Lakes P Forum. There are changes that have occurred in the lakes and tributaries in the past 15 yr that indicate a greater need to focus on non-point sources, whether urban or rural. Changes have also occurred in land management to reduce non-point P losses from agriculture. While these changes have reduced sediment and particulate P loading in some Ohio tributaries, the more bioavailable, dissolved P forms have increased. As there is incomplete knowledge about the mechanisms that are influencing algal growth, it could be a challenge to demonstrate, in the near term, improvements in water quality with further P reductions from agriculture alone. Regardless, there appears to be a desire for improved accountability and transparency for agricultural non-point source P management.
Van Esbroeck C.J.,University of Waterloo |
Macrae M.L.,University of Waterloo |
Brunke R.I.,Environmental Management Branch |
McKague K.,Environmental Management Branch
Journal of Great Lakes Research | Year: 2016
Phosphorus (P) export from agriculture fields is contributing to algal blooms within Lake Erie. Field data quantifying the magnitude, timing and pathways of P loss are required to develop and test solutions. This study quantifies annual and seasonal losses of dissolved (DRP) and total (TP) phosphorus in surface runoff and tile drainage from three reduced tillage fields (October 2011 to April 2013). The non-growing season (NGS, October to April) was a critical period, with 83 to 97% of annual combined [surface + tile] runoff; 84 to 100% of DRP loss; 67 to 98% of TP loss occurring in this time. Annual export (May 2012 to April 2013) ranged from 0.332 to 0.419. kg TP/ha/yr and 0.034 to 0.096. kg DRP/ha/yr. Tile drainage contributed the majority of annual water export from fields (78 to 90%) whereas surface runoff contributed little (10 to 22%). Tiles exported 0.169 to 0.255. kg TP/ha/yr (40 to 77% of total TP load) and 0.017 to 0.023. kg DRP/ha/yr (19 to 67% of total DRP load). Thus, surface runoff, which primarily occurred during winter thaws, exported disproportionately more P relative to its contribution to flow. Phosphorus losses in tile drain effluent monitored over an additional NGS (October 2011 to April 2012) were elevated at two sites following the fall application of P. This study provides an improved understanding of edge-of-field P losses in humid, cold temperate regions that experience significant winter periods, and provides estimates of P loads from fields in which P conservation strategies are employed. © 2016 International Association for Great Lakes Research.
Kinnear J.E.,Number 9 Valley Road |
Krebs C.J.,University of Canberra |
Pentland C.,Edith Cowan University |
Orell P.,Environmental Management Branch |
And 2 more authors.
Wildlife Research | Year: 2010
Predation is widely believed to be the main threatening process for many native vertebrates in Australia. For 25 years, predator-baiting experiments have been used in the Western Australian Central Wheatbelt to control red fox predation on rock-wallabies and other endangered marsupial prey elsewhere. We review here the history of a series of baiting experiments designed to protect rock-wallaby colonies by controlling red foxes with 1080 poison baits. We continue to support the conclusion that red foxes can reduce or exterminate rock-wallaby populations in Western Australia. Research trials from 1990 to 2008 have uniformly shown a dramatic recovery of rock-wallaby populations once red foxes are baited. Baiting experiments are often black boxes and their success should not blind us to their weaknesses. Ideally, what we would like to measure are the functional responses of predators to prey abundance directly. As a contribution towards this goal, we describe new technology that enables one to determine which predator killed which prey, at exactly what time, with improved research and management outcomes. © CSIRO 2010.
Hecht A.D.,U.S. Environmental Protection Agency |
Fiksel J.,U.S. Environmental Protection Agency |
Fulton S.C.,U.S. Environmental Protection Agency |
Yosie T.F.,World Environment Center |
And 4 more authors.
Sustainability: Science, Practice, and Policy | Year: 2012
Although the world faces serious environmental, economic, and social challenges, we believe that a combination of science and innovation, effective governance, and public-private collaboration can help to overcome many of them and achieve sustainable development. Numerous government policies are now promoting sustainable management practices, while many people in the business and financial communities view sustainability as a means to reduce long-term risk, enhance competitiveness, and promote social well-being. Advances in science and technology are creating new economic opportunities and producing sustainable solutions, while expanded public access to global data and information is helping to shape business and government policies. Looking ahead, sustainability will be best pursued by building on these trends and encouraging new collaborative initiatives among governments, businesses, and the nonprofit sector. This article is an example of a collaboration that includes government, business, academic, nongovernmental, and international organizations. © 2012 Gram-Hanssen & Christensen.
Luken R.A.,UNIDO |
Van Berkel R.,Resource Efficient and Cleaner Production Unit |
Leuenberger H.,Environmental Management Branch |
Schwager P.,Resource Efficient and Cleaner Production Unit
Journal of Cleaner Production | Year: 2016
In the framework of their joint global Cleaner Production Programme, the United Nations Industrial Development Organization and the United Nations Environment Programme officially established the first eight National Cleaner Production Centres in 1995. In 2015 there are 58 centres operating in 56 countries. This article, based on a 2014 structured questionnaire completed by 41 out of the 50 centres established between 1995 and 2011, reports on how their expectations about a world-wide programme played out over the 20 years since its official launch. Two of their twelve expectations were exceeded; five were met; two were partially met and two were not met. Four unanticipated activities expanded the environmental services provided by the centres. Meeting the two documented unmet expectations - that the services should green entire industrial sectors and result in measurable improvements in environmental quality - will require the centres to deepen their effective impact on entire industrial sectors by scaling up the application of Cleaner Production and mainstreaming its policy, financial and related incentives. They will need to take on catalytic roles in nationally significant strategies for the resource-efficient greening of industry, which would require finding a balance between public good service delivery, aimed at putting cleaner production and resource efficiency on the agenda of industry, and applied sector and company specific service delivery for revenue generation and the benefit of companies. © 2015 Elsevier Ltd. All rights reserved.
Adams J.R.,University of Guelph |
Adams J.R.,Agriculture and Agri Food Canada |
Rowlandson T.L.,University of Guelph |
McKeown S.J.,University of Guelph |
And 3 more authors.
Canadian Journal of Remote Sensing | Year: 2013
This study evaluates the utility of the Cloude-Pottier and Freeman-Durden scattering decompositions for providing agricultural land surface information during autumn months using C-band polarimetric RADARSAT-2 data. We applied these decompositions over 94 agricultural fields in Southern Ontario, Canada, to characterize scattering mechanisms from unharvested senesced crops and harvested fields with three generalized soil tillage practices. The decompositions were applied to RADARSAT-2 images over six dates during October and November 2010 at high (49°) and low (23°) incidence angles. Agreement was found between the decompositions for the identification of primary (volume and rough surface scatter) scattering mechanisms for the senesced unharvested crops and the harvested fields. Significant statistical separability was observed between the strengths of decomposition parameters when comparing (i) senesced unharvested crops to post-harvest conventional tillage fields and (ii) post-harvest no tillage fields to post-harvest conventional tillage fields. These results suggest that high accuracy classifications may be possible with these data; however, weak separability was observed when comparing fields with conservation tillage. The strongest separability was observed with Entropy and α-angle of the Cloude-Pottier decomposition and the rough surface scattering component of the Freeman-Durden decomposition, suggesting sensitivity of these parameters to surface roughness and crop residue. Results also demonstrated that superior separability was found with the data at the higher 49° incidence angle in contrast to data acquired at the lower 23° incidence angle imagery. © 2013 CASI.